Mon·Nov 15, 2021Monday·November 15, 2021

1. 01*

   The flux tube profile in full QCD

   M. Baker🇺🇸 · V. Chelnokov🇩🇪 · L. Cosmai🇮🇹 · F. Cuteri🇩🇪 · A. Papa🇮🇹

   We measure the spatial distribution of all components of the color fields surrounding a static quark antiquark pair in QCD with (2+1) HISQ flavors. We isolate the nonperturbative component of the longitudinal chromoelectric color field responsible for the linear term in the confining potential.

   hep-lathep-phPoS(2022)·5 citations
2. 02*

   Fermionic quantum field theories as probabilistic cellular automata

   C. Wetterich🇩🇪

   A class of fermionic quantum field theories with interactions is shown to be equivalent to probabilistic cellular automata, namely cellular automata with a probability distribution for the initial states. Probabilistic cellular automata on a one-dimensional lattice are equivalent to two - dimensional quantum field theories for fermions. They can be viewed as generalized Ising models on a square lattice and therefore as classical statistical systems. As quantum field theories they are quantum systems. Thus quantum mechanics emerges from classical statistics. As an explicit example for an interacting fermionic quantum field theory we describe a type of discretized Thirring model as a cellular automaton. The updating rule of the automaton is encoded in the step evolution operator that can be expressed in terms of fermionic annihilation and creation operators. The complex structure of quantum mechanics is associated to particle -- hole transformations. The naive continuum limit exhibits Lorentz symmetry. We exploit the equivalence to quantum field theory in order to show how quantum concepts as wave functions, density matrix, non-commuting operators for observables and similarity transformations are convenient and useful concepts for the description of probabilistic cellular automata.

   hep-lathep-thquant-phPRD(2022)·18 citations
3. 03*

   Form factors for the decay processes $B_c^{+}\to D^0{\ell }^{+}{\nu }_{\ell }$ and $B_c^{+}\to D_s^{+}{\ell }^{+}{\ell }^{-}$ from lattice QCD

   Laurence Cooper🇬🇧 · Christine Davies🇬🇧 · Matthew Wingate🇬🇧

   We present results of the first lattice QCD calculations of the weak matrix elements for the decays $B_c^{+}\to D^0{\ell }^{+}{\nu }_{\ell }$, $B_c^{+}\to D_s^{+}{\ell }^{+}{\ell }^{-}$ and $B_c^{+}\to D_s^{+}\nu \overline{\nu }$. Form factors across the entire physical $q^2$ range are then extracted and extrapolated to the continuum limit with physical quark masses. Results are derived from correlation functions computed on MILC collaboration gauge configurations with three different lattice spacings and including 2+1+1 flavours of sea quarks in the Highly Improved Staggered Quark (HISQ) formalism. HISQ is also used for all of the valence quarks. The uncertainty on the decay widths from our form factors for $B_c^{+}\to D^0{\ell }^{+}{\nu }_{\ell }$ is similar in size to that from the present value for $V_{ub}$. We obtain the ratio $\Gamma (B_c^{+}\to D^0{\mu }^{+}{\nu }_{\mu })/{\left|{\eta }_{\mathrm{EW}}{V}_{ub}\right|}^2=4.43(63)\times 10^{12}{\mathrm{s}}^{-1}$. Combining our form factors with those found previously by HPQCD for $B_c^{+}\to J/\psi {\mu }^{+}{\nu }_{\mu }$, we find ${\left|V_{cb}/V_{ub}\right|}^2\Gamma (B_c^{+}\to D^0{\mu }^{+}{\nu }_{\mu })/\Gamma (B_c^{+}\to J/\psi {\mu }^{+}{\nu }_{\mu })=0.257(36{)}_{B_c\to D}(18{)}_{B_c\to J/\psi }$. We calculate the differential decay widths of $B_c^{+}\to D_s^{+}{\ell }^{+}{\ell }^{-}$ across the full $q^2$ range, and give integrated results in $q^2$ bins that avoid possible effects from charmonium and $u\overline{u}$ resonances. For example, we find that the ratio of differential branching fractions integrated over the range $q^2=1{\mathrm{GeV}}^2-6{\mathrm{GeV}}^2$ for $B_c^{+}\to D_s^{+}{\mu }^{+}{\mu }^{-}$ and $B_c^{+}\to J/\psi {\mu }^{+}{\nu }_{\mu }$ is $6.31(90{)}_{B_c\to D_s}(65{)}_{B_c\to J/\psi }\times 10^{-6}$. We also give results for the branching fraction of $B_c^{+}\to D_s^{+}\nu \overline{\nu }$.

   hep-latPoS(2022)·1 citation
4. 04*

   Semileptonic transitions: $B_{(s)}\to \pi (K)$; $D_s\to K$; $D\to \pi ,K$; and $K\to \pi$

   Zhao-Qian Yao🇨🇳 · Daniele Binosi🇮🇹 · Zhu-Fang Cui🇨🇳 · Craig D. Roberts🇨🇳

   Continuum Schwinger function methods for the strong-interaction bound-state problem are used to arrive at a unified set of parameter-free predictions for the semileptonic $K\to \pi$, $D\to \pi ,K$ and $D_s\to K$, $B_{(s)}\to \pi (K)$ transition form factors and the associated branching fractions. The form factors are a leading source of uncertainty in all such calculations: our results agree quantitatively with available data and provide benchmarks for the hitherto unmeasured $D_s\to K^0$, ${\bar{B}}_s\to K^{+}$ form factors. The analysis delivers a value of $|V_{cs}|=0.974(10)$ and also predictions for all branching fraction ratios in the pseudoscalar meson sector that can be used to test lepton flavour universality. Quantitative comparisons are provided between extant theory and the recent measurement of ${\mathcal{B}}_{B_s^0\to K^{-}{\mu }^{+}{\nu }_{\mu }}$. Here, further, refined measurements would be useful in moving toward a more accurate value of $|V_{ub}|$.

   ↳ hep-phhep-exhep-latnucl-ex+1PLB(2022)·19 citations
5. 05*

   The QCD Adler function and the muon $g-2$ anomaly from renormalons

   Alessio Maiezza🇭🇷 · Juan Carlos Vasquez🇺🇸

   We describe the Adler function in Quantum Chromodynamics using a transseries representation within a resurgent framework. The approach is based on a Borel-Ecalle resummation of the infrared renormalons combined with an effective running for the strong coupling. The new approach is flexible enough to give values in agreement with the current Adler function determinations. We then apply our finding to the muon's anomalous magnetic moment studying the possibility of saturating, solely in terms of the vacuum polarization function, the current discrepancy between the best Standard Model value for the muon's anomalous magnetic moment and the experimental value obtained by the most recent muon g-2 collaboration. The latter shows that the Adler function's new representation can also be consistent with recent lattice determinations.

   ↳ hep-phhep-lathep-thSymmetry(2022)·7 citations
6. 06*

   Short-Distance Structure of Unpolarized Gluon Pseudodistributions

   Ian Balitsky🇺🇸 · Wayne Morris🇺🇸 · Anatoly Radyushkin🇺🇸

   We present the results that form the basis for calculations of the unpolarized gluon parton distributions (PDFs) using the pseudo-PDF approach. We give the results for the most complicated box diagram both for gluon bilocal operators with arbitrary indices, and for combinations of indices corresponding to three matrix elements that are most convenient to extract the twist-2 invariant amplitude. We also present detailed results for the gluon-quark transition diagram. The additional results for the box diagram and the gluon-quark contribution may be used for extractions of the gluon PDF from different matrix elements, with a possible cross-check of the results obtained in this way.

   ↳ hep-phhep-latPRD(2022)·18 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.